A clamping device of this type is known from DE 100 43 006 C1. There, the machine tools are held by mean of a clamping set arranged in the working spindle, which clamping set is arranged at the front end of a drawbar placed under prestress by means of a spring arrangement. The clamping set commonly comprises several radially movable gripper elements by means of which the machine tool is drawn into the working spindle. In order to release the machine tool, the drawbar is displaced by means of a releasing unit against the force of the spring arrangement, such that the clamping set with gripper elements is opened and releases the machine tool. The releasing unit comprises a hydraulically operated piston-cylinder arrangement by means of which the clamping set can be moved by the drawbar into the released position against the force of the spring arrangement. However, this necessitates relatively expensive supply aggregates and hook-ups or connections in order to supply the releasing unit with hydraulic fluid. In addition, special sealing measures must be provided.
Known from DE 101 01 093 A1 is a clamping device featuring an electric motor operating device to operate the drawbar. However, no spring arrangement is provided to generate the drawing force of the clamping set for this known clamping device.
The problem of the invention is to create a clamping device of the aforementioned type that enables simplified operation.